Public bug reported:
The issue happens on lucid instances running on ec2. Loading
/usr/lib/libgomp.so.1 takes a long time (~10 seconds) and the following
warning appears in dmesg:
** WARNING: Currently emulating unsupported memory accesses **
** in /lib/tls glibc libraries. The emulation is **
** slow. To ensure full performance you should **
** install a 'xen-friendly' (nosegneg) version of **
** the library, or disable tls support by executing **
** the following as root: **
** mv /lib/tls /lib/tls.disabled **
To reproduce:
- launch a lucid instance from ami-a403f7cd
- apt-get install libgomp1
- load /usr/lib/libgomp.so.1, eg
perl -MDynaLoader -e 'DynaLoader::dl_load_file("/usr/lib/libgomp.so.1")'
or run an executable that uses it, eg 'convert' from the imagemagick package.
A weird thing is that libgomp1 seems to be normally using the nosegneg
version:
ldd /usr/lib/libgomp.so.1
linux-gate.so.1 => (0xb77e2000)
librt.so.1 => /lib/tls/i686/nosegneg/librt.so.1 (0xb77c1000)
libpthread.so.0 => /lib/tls/i686/nosegneg/libpthread.so.0 (0xb77a8000)
libc.so.6 => /lib/tls/i686/nosegneg/libc.so.6 (0xb764a000)
/lib/ld-linux.so.2 (0xb77e3000)
Is it a false warning? Deleting /lib/tls does not help.
Note also that on maverick (ami-1a837773) this issue does _not_ exist,
and ldd output is different:
ldd /usr/lib/libgomp.so.1
linux-gate.so.1 => (0xb779f000)
librt.so.1 => /lib/librt.so.1 (0xb7780000)
libpthread.so.0 => /lib/libpthread.so.0 (0xb7766000)
libc.so.6 => /lib/libc.so.6 (0xb7608000)
/lib/ld-linux.so.2 (0xb77a0000)
ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: libc6-xen 2.11.1-0ubuntu7.5
ProcVersionSignature: Ubuntu 2.6.32-309.18-ec2 2.6.32.21+drm33.7
Uname: Linux 2.6.32-309-ec2 i686
Architecture: i386
Date: Sun Oct 31 16:52:41 2010
Ec2AMI: ami-a403f7cd
Ec2AMIManifest:
ubuntu-images-us/ubuntu-lucid-10.04-i386-server-20101020.manifest.xml
Ec2AvailabilityZone: us-east-1b
Ec2InstanceType: m1.small
Ec2Kernel: aki-6603f70f
Ec2Ramdisk: unavailable
ProcEnviron:
PATH=(custom, no user)
LANG=en_US.UTF-8
SHELL=/bin/bash
SourcePackage: eglibc
** Affects: eglibc (Ubuntu)
Importance: Undecided
Status: New
** Tags: apport-bug ec2-images i386 lucid
--
slow emulation warning when loading libgomp.so.1
https://bugs.launchpad.net/bugs/669160
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